Australian and Scottish researchers say modifying beta-glucan levels in barley may help contribute to lower cholesterol
A team of scientists has shown the potential to rapidly improve barley quality through the gene editing technique called CRISPR.
Researchers at the University of Adelaide’s Waite Research Institute, working with colleagues at the James Hutton Institute in Scotland, recently showed how the levels of beta-glucan, a source of fermentable dietary fibre that may contribute to lowering cholesterol, can be modified by gene editing.
Barley is Australia’s second-most important cereal crop behind wheat, contributing around $3 billion to the economy.
In Canada, about eight million tonnes of barley are produced each year. It is used for human food, livestock feed, and as malt to brew beer.
“Beta-glucan content in barley grain definitely varies depending on the cultivar,” said associate professor Matthew Tucker, deputy director of the Waite Research Institute. “Previous studies have shown this can vary anywhere from two percent to nine percent and a lot of this is due to the underlying genetics.
“However, the environment also has an impact on beta-glucan content. The same cultivar can be grown in different locations and years and show variation, particularly if there are frost or drought events.”
He said breeders in Australia have worked hard to reduce the levels of beta-glucan to between three and five percent because it is preferred by the malting and brewing industries.
He said new genetic solutions that enable breeders to control beta-glucan levels more efficiently would be sought after.
The research team used CRISPR to target genes potentially involved in controlling beta-glucan composition. Researchers tried first to “turn off” the genes by introducing changes in the DNA that stop gene function.
“This approach probably worked too well, since beta-glucan levels were so low it was difficult to detect beta-glucan in the gene-edited plants,” he said. “In follow-up studies we plan to target different regions of the beta-glucan genes to reduce gene activity rather than remove it completely.
“We are also looking at ways to edit the gene such that it becomes more active. We speculate this could lead to higher beta-glucan levels that are ideally suited to heathy foods for human consumption.”
To generate changes in the gene family responsible for beta-glucan, they used an approach called reverse genetics. Tucker said that the approach is where scientists search for genes that might be controlling a specific trait by looking at when and where they are turned on or off during growth.
“This study provided evidence to show that gene editing can be a useful tool for changing grain composition in barley and showed that there were no unexpected effects of the edits,” said Tucker.
Grains from gene edited plants are now being gathered and stored for a field trial in 2021.
The study so far reported on results from gene edits in a European cultivar (Golden Promise), but an Australian cultivar ideally suited to local conditions has received the same edits.
“The key considerations for Australian growers are yield constraints such as frost, disease and drought. In an average year, when solid yields are expected, grain quality becomes a pressing issue. The next generation of barley cultivars will hopefully show genetic improvements that enable them to overcome yield constraints imposed by the environment, in addition to showing optimal grain quality parameters that make them well-suited to specific export markets.”
The research was published recently in The Plant Journal.